This report discusses about different types of tools that are required for cutting stones. This is a study project that was done in 5th semester of B.Tech. for subject Manufacturing Process and Metallurgy.

1. G D GOENKA UNIVERSITY
MANUFACTURING PROCESS &
METTULURGY
STUDY PROJECT TOPIC:
CUTTING TOOLS USED FOR CUTTING OF
STONE
SUBMITTED TO: SUBMITTED BY:
HARDEEP SINGH PRAVESH TANEJA
(ASSISTANT PROFESSOR) 130020201057

2. INTRODUCTION
AN AMAZING INVENTION
Diamond coated wires comprise diamond beads threaded on a high tensile steel
supporting cable. The diamond beads are made by fixing a diamond layer around a
cylindrical steel support.
Nearly 30 years ago, Diamant Boart invented the first diamond wire for the
extraction of marble in quarries. From the entry into service of the first wires at
Carrara, success was immediate, in a few months all the quarries abandoned their
helical wire sawing installations to make way for the new diamond wire cutting
equipment.
During the 1980s, Diamant Boart were the first to introduce a diamond wire into
granite quarries. It was an immediate success, to the point that, today most granite
quarries have adopted this new procedure. Later on Diamant Boart began to
develop wires for squaring the blocks and then cutting them into thick slabs.
Marble and granite producers very quickly discovered the advantages of these new
products.
The recent launch of multiwire machines is the opportunity for Diamant Boart to
put on the market a new diamond wire specifically designed for these machines
and which is of the high quality that is required for this application.

3. We focus all our energy on improving your work situation. Consequently our
objectives are high accessibility; prompt service, exact deliveries and perfect
cutting results.
Diamond Wires
WIRES FOR MARBLE QUARRIES
Two types of diamond beads – two uses suitable for the extraction of marble.
The electrolytic wire was the first cable placed on the market. Its beads are made
from an annular steel support onto which the diamond grains are electrolytically
deposited; they are remarkably robust and sharp.
The electrolytic wire is perfectly suitable for sawing marbles; it is especially
appreciated for small cuts and for cutting blocks (small radii of curvature).
Compared to the sintered wire, the electrolytic wire offers the double advantage of
needing only 25 horsepower and reduced water spraying (from 10l/min to
20l/min). It is also used when the customer wants a high cutting speed.
The diamond-sintered wire is designed to cut all types of rock (including the
hardest and the most abrasive) and to increase the number of m2
sawn (some are
described as “long life” wires). The active part of the beads is a ring of sintered
diamond, whose composition is like the segments used in blades and discs.

4. Technological advantage: the sawing speed of a wire is practically constant
throughout its lifetime. The sintered wire requires a minimum power of 40 hp and
normal water spraying, between 20 to 50l/min according to the cut dimensions.
TWO TYPES OF WIRE FOR MARBLE EXTRACTION.
1. ASYMMETRICAL FITTING
The spring inserted between the bush crimped on the cable and the bead dampens
the shocks experienced by the latter and reduces their impact on the supporting
cable. For this reason, the cable must turn in the direction of rotation indicated by
the arrow.

5. 2. SYMMETRIC FITTING.
A spring fitted on both sides of the bush protects the assembly from shocks. This
cable can turn in both directions without danger.
PERFORMANCE

6. 3. HIGH SPEED WIRE
Increasing the sawing speed provides the marble producer with an appreciable
benefit resulting from reductions in energy and water consumption and operator
costs.
As an example the table below shows that an increase in speed from 11 to 16 m2/h
can bring a benefit in the case of extraction of compact marble (reference: standard
sawing cost = 100).
To increase the wire sawing speed, Diamant Boart is working on the optimum
combination of the best performing diamonds and the most suitable metallic bonds
for a material type. This therefore updates solutions for each use.
COMPARISON OF SAWING COSTS PER M2
SAWN

7. WIRES FOR GRANITE QUARRIES
Except for small cuts made in marble quarries, all other applications of diamond
wires use beads with diamond concretions.
For granite quarries, the cables are in general fitted by injection of a vulcanised
rubber, whereas cable used in granite and marble sawing works are more often
injected with plastic. The more difficult to implement and costly rubber injection is
preferred for cables used in granite quarries, for the following reasons :
 The vulcanised rubber adheres better to the beads and support cable, which
protects it better from the action of abrasive pastes, in particular when the
cable takes up small radii of curvature (beginning and end of quarry cuts),
 The vulcanised rubber easily withstands increases in temperature caused by
badly controlled water spraying, which often happens in a quarry, whereas
plastic softens and looses its strength properties,
 The flexibility of a cable fitted with rubber is greater, which reduces the risk
of irregular wearing of the beads (ovalisation phenomenon).

8. WIRES FOR STATIONARY MACHINES
1. Squaring and cutting of blocks using diamond wire.
Diamond wire is now generally used in most workshops.
There are many reasons for this:
 The wire allows significantly greater sawing heights than large discs,
 The wire saw in width is thinner and more precise than the large disc
(deviation < 1 mm),
 The investment in a wire machine is relatively low,
 By virtue of its greater and greater reliability, wire sawing technology is
more and more automated and thus becomes just as productive as competing
techniques,
 Noise nuisance generated by diamond wire sawing is significantly less than
that produced by other sawing techniques.
Recommendations
 For optimum use of diamond wire, Diamant Boart supply detailed operating
instructions. These are the essential elements:
– the rotation of the wire about itself should be regularly checked
(clothes peg or paint line method),
– the bead wear profile should be regularly inspected (avoid ovalisation
and coning of the beads),
– the connections should be changed whenever excessively high wear of
the adjacent beads is noted and whenever it is necessary to apply
pretorsion to the cable,

9. – the cable tension is set to 250–300 kg for 4 and 5 mm diameter
supporting cables
– adjust the linear speed of the wire to the material being sawn :–
granite class 1 – 2 : 25–30 m/sec– granite class 3 – 4 : 22–26 m/sec–
granite class 5 : 20–22 m/sec– marble : 30–35 m/sec– abrasive rocks :
30–35 m/sec
– water spraying of the diamond wire is an essential criterion for good
sawing : depending on the blocks the water flow rate to be provided
is between 15 and 25 l/min.
– during the sharpening of a new wire, the linear speed must be reduced
by 2 to 3 m/sec relative to the speeds given above.
WIRES FOR PROFILING MACHINES
Profiling – a complementary application for stationary machines.
The introduction of new numerically controlled machines allows the shaping of
complex forms in large production runs for gravestones and building. The use of
diamond wire for shaping makes possible the optimum use of excellent quality
materials that are discarded from the production of slabs and paving stones.
The low cost of the cuts, the profiling precision and the surface quality
indisputably make diamond wire very competitive. The diamond wire used in
profiling machines is similar to that found in stationary machines, but it is
generally of a smaller diameter (8.3 mm). Performance is slightly inferior to that of
cables for stationary machines.
Recommendations.
For operating parameters refer to the recommendations given in the chapter on
stationary machines. The parameters are nevertheless adjusted to the particular
requirements of the (desired) cut.

11. WIRES FOR MULTIWIRE MACHINES
To saw granite into thin slabs, the classical procedure using a grit-set frame is often
chosen for two main reasons, namely a very competitive cost and a well
understood procedure.
However, the drawbacks remain obvious : limited productivity (7 cm/hour) and
thus poor flexibility, water recycling, labor costs and increase in the sawing costs
per m2 for thick slabs and of course a large installation area.
These disadvantages associated with the grit-set frame have led to many attempts
to derive a diamond based alternative. By far the most successful is the multiwire
sawing machine.
ADVANTAGES
With the new wires customers gain a decrease in the sawing costs and an improved
productivity. Moreover, to avoid the long and costly remounting operations the 7.3
mm is “one use”.
RECOMMENDATIONS
For optimum use the following is necessary.
 The blocks have to be squared at the top and the bottom before sawing.
 The minimum block length has to be 2.5 m or more.
 The blocks have to be installed and cemented on three wooden support.
CHARACTERISTICS
The standard wires for multiwires machines are injected with transparent plastic
and they contain 36 beads/m. In general, they are not sharpened.

12. WHAT TYPE OF CONNECTION?
The most common way of closing a diamond wire is to crimp to the ends tubes or
steel parts to be screwed up. Diamant Boart offer a complete range of standard
connections with the equipment needed to crimp them to the cables.

13. DIAMOND BLADES
Fast cutting diamond blades are available in diameters 115 to 3500 mm.
Different materials represent different challenges and Diamant Boart’s vast range
of specified bonds along with a choice of standard noise reduced steel centers
provide perfect solutions.
We particularly recommend that the blade to be used should suit the material to be
cut. Each material or group of material has its own particular hardness and abrasive
properties.
The type of blade is determined by these two factors. Therefore it is easy to foresee
that a change of material can be fatal to the tool life. A blade intended to cut
marble, for example, will be completely worn after sawing a few square meters of
soft sandstone, which is softer but more abrasive than marble.
Especially developed to cut all kind of granite, marble and other stones our blades
will respond to all and even more than you demand. The correct identification of
the material to cut is the most important factors for choosing a tool.

14. THE BLADE AND THE CORE
The blade
Description.
A diamond blade consists of two parts :
the diamond segments and the blade center
The core
Different kinds of core.
The standard core. The steel center is a high-grade heat-treated, tempered steel
disc; to meet highest demands on stability and wear resistance. The steel center
width prevents wobbling of the blades.
The silent core. The silent core is constituted from 2 sheets of steel separated by a
sheet of copper to enable an improvement of 6-9 dBA in noise level.

15. THE SEGMENTS
The segments contain a mixture of diamonds and metal powder. During the
manufacturing process, the metal powder and diamond mixture is compressed in
order to obtain a solid metal alloy which holds the diamonds. The segment is
slightly wider than the core, to allow the attacking edge to penetrate the material
without the steel rubbing against it.
ATTACHING DIAMOND SEGMENTS TO THE STEEL CORE
The diamond segment can be attached to the steel centre using two basic methods.
Brazing.
The segments are attached to the core by brazing with silver solder.
 Used on standard blades for wet cutting
 Do not use for dry cutting !
Laser-welding.
Segments are welded to the centre using a laser beam.
 Strongest bond possible between steel centre and segment
 Suitable for wet and dry cutting applications. The laser-welding
process is the latest state of the art method to attach diamond
segments to the blade centre. This process assures a maximum
degree of safety.

16. FINISHING OPERATIONS
After the assembling process, each individual segment undergoes double-sided
cross-bend tests to ensure that they are solidly fused to the centre.
Tension must be put on each blade to assure that it runs straight and true even
under tough cutting conditions.
Each blade is tensioned by hand; a process performed by specialists who are
skillfull experts in their craft.
Each blade is sharpened, at the factory to make sure that the blade will cut freely,
the very first time your customer will put it to use.
The last steps - finishing, painting, printing and packing - are performed with the
same amount of care and concern for quality as you already have seen in the
manufacturing process.
BLADES VARIABLES
SEGMENT HARDNESS
 Softer bonds tend to cut faster but have a shorter life
 Harder bonds tend to cut slower but have a
longer life.
SEGMENT SIDE CLEARANCE
The balanced ratio between widths of segment and steel centre assures sufficient
discharge of material and even wear of segments and prevents jamming of the
blade in the material.
Thinner blade segments tend to cut faster but give shorter life.
Thicker blade segments tend to cut slower but give longer life.
The reason is very simple : thinner blade segments have less surface area in contact
with the material and offer less resistance as they grind through the material.
CUTTING VARIABLES
1. CUTTING SPEED
It is important to adjust the feed speed so that it corresponds the recommended
cutting speed expressed in cm2/min.

17. 2. CUTTING DEPTH
Depth of cut and feed speed should be combined so as to respect the recommended
cutting speeds (cm2/min) for the particular type of material.
3. FORWARD FEED
This one depends on the already chosen cutting depth (high speed combined with a
shallow cutting depth sharpen the tool).
MACHINE VARIABLES
1. Watering
The water pressure is of little importance compared to the quantity. Therefore,
abundant watering is recommended.
2. Power.
Should be determined by the blade diameter and type of material cut.
3. Peripheral speed.
The peripheral speed should be selected according to hardness and abrasiveness of
the material to be cut; together with the feed speed it affects the cutting speed and
the tool life. It is therefore important to suit the peripheral speed to the material to
be sawn.

18. GANG SAW BLADES
For the precision cutting of natural stone, the gang saw blades of variable
dimensions and characteristics are cater for all types of marbles and other material
plants (except granite)for exactly-dimensioned blocks and slabs.
The blade life and quality of the cut largely depend on the care and precision with
which the set of blades has been fitted to the frame.
Time devoted to correct mounting of the blades will pay later when the sawing
takes place.
Diamant Boart introduced the first diamond gang saw blade in 1955 and the thin
gang saw blades in 2002. The great advantage of those thin gang saw blades is the
real saving achieved on the total sawing cost by obtaining additional m2 per block.
Further development will be introduced on the market.

19. Hammer and Chisel
HAMMERS
With the advent of iron - and later steel - the efficiency of carving marble and stones of similar
hardness improved, and the most common types of hammers and chisels for carving by hand
have since remained almost unchanged.
There have been some improvements such as tungsten carbide inserts for chisel tips that allow
carving of harder stones like granite, but high carbon tool steel is still preferred by many carvers
for working in more responsive marble and similar types of stone.
Aside from the shape of the striking end, the Hammer Head chisel differs from the Mallet
Headed type in that the cutting edge of the tool only is hardened and tempered, while the shank
of the tool is left unhardened. This is to allow the shank a certain amount of

20. resilience when working hard stone under the blows of a hardened steel Hammer - i.e., the
shank will bend rather than break . . . when between the rock and the hard place!
CARVING CHISELS
Many sculptors might use chisels like those above for all their work when stone carving,
managing quite well with the wide selection available in those basic types of chisel. However,
for those sculptors working in large blocks of stone or who often get stone cut-to-order for
commission work there are a couple of additional types of chisel that might be used. During the
initial stages of working on a dimensionally-cut block sometimes very large amounts of waste
need to be removed before carving, as such, begins.
One of these specialized chisels is the Tracer or Line Tracer, which looks like a very stout and
oversized Flat Chisel. It is used to 'trace' a line across or around a cut block of stone to create a
weakened area, allowing a controlled fracture of the block. It is repeatedly placed perpendicular

21. to the surface of the stone along adjoining segments of the intended split line and at each
placement struck a blow with a heavy hammer.
The Pitching Tool - aka, the Pitcher or Hand Set - is also used to remove a great deal of waste
material at the initial stages of carving, but only if the carving block has flat-sawn faces. The
'working-edge' of the Pitching Tool is a broad flat face that usually is ground to an angle just
slightly-off the perpendicular.
A small version of the Pitching Tool that has the cutting face offset from the centre axis of the
shank is called a Chipper. This offset is to allow clearance when doing a 'finishing' pitch
following the work of the larger Pitching Tool.

22. 1. HAND CARVING CHISELS:
THE POINT
The Point or the Punch is used after any initial work with the tracer or the pitching tool. The
Point and the Punch are used to rough-out the form. The Point differs from the Punch in that the
latter tapers to a small cutting edge where the former tapers to a single point.

23. The manner in which the chisel is gripped varies according to regional traditions, personal
preferences, or to the type of work being done.
2. HAND CARVING CHISELS:
The Tooth Chisel or Claw is used after the coarse carving with the Point.Following the roughing-
out, the Toothed Chisels are used to further define the surfaces of the form. Beginning with
varieties that have a few large teeth — such as the two-toothed Calcagno pictured at the far left
above — and following successively with versions that have both more numerous and finer
teeth, the Tooth Chisel is used to refine the form and make the surface contours more uniform
and regular.

24. The toothed chisel, with its row of pointed teeth, acts like a rake to even out the surface
irregularities left by the point. During use the chisel’s teeth should all be in contact with the stone
in order to prevent breakage.

25. A couple of manufacturers make Skutch Holders in three sizes which allows for a quick change
between replaceable inserts of either coarse or fine cutting teeth, or a plain flat cutting edge.

26. 6. TRADITIONAL PROCESSES:
HAND CARVING CHISELS
The Flat Chisel is primarily used to follow and refine the work of the toothed chisel. It is used to
flatten surfaces, to crisp-up edges and intersections of planes, and to incise lettering.
The Cape Chisel — also called a Splitter — has a narrow blade (1/8-inch to 3/8-inch wide) that
swells and thickens in the opposite dimension about one inch away from the cutting end of the
chisel. This extra steel strengthens the cutting end of the relatively narrow tool and allows it to

27. be struck with fairly powerful blows without damaging the tool. It is used for cutting narrow
grooves or hollows into the surface.
The Bolster or Drove, a Flat Chisel that is two-inches wide or more, is used when working broad,
flat areas.
The Rondel, Round, or Bullnose Chisel is used in much the same manner as the Flat Chisel
except it is used for flattening concave surfaces and working into intersections of curved
planes. The curved corners of theRondel allow curved hollows to be worked without marring the
adjacent surfaces.

28. The Gouge is used in much the same manner as theRondel, though allowing a greater control
over the uniformity of the cut. The Gouge is used primarily when working softer stones or when
doing architectural carving of mouldings, when its contoured cutting edge can be more
effectively used to achieve uniformity.
SURFACING TOOLS:-
The Pick is used to chip away at the surface of the stone, either
to make it more uniform or to shape it in a rough manner much
as the Point Chisel might be used.
The Pick can remove material more quickly than the Point, but
the degree of control it affords the carver is somewhat less.
For this reason the use of the
Pick is usually limited to the initial roughing-out stages of
the carving, although it can be used to provide an irregular
texture to areas that are deliberately left to appear as
only roughly worked from the 'natural' contours of the stone.

29. One tool made specifically for sculptors combines the Pick with another surfacingtool,the Bush
Hammer.
The Bush Hammer, sometimes called a Facing
Hammer, is used to pulverize the surface of the
stone, evening-out
The Bush Hammer has several rows of pyramidal teeth on its
faces, which crush the surface of the stone and leave a distinctive
texture. In use the tool serves to even-out the contrast of high
and low points, softening the surface contours making them more
uniform.
Because tool steel is about the same hardness as granite — about
6.5 to 7 on the Mohs’ scale of hardness — granite and similar

30. stones cannot be practically carved with common steel carving chisels.
When the hardest carving chisels were made
only from tool steel, the pulverizing action
of the Bush Hammer was the primary means
of shaping granite or hard stone.
The type of monolithic form that the nature
of this tool permitted the carver to work into
granite was generally more dense and
compact in overall design than similar
subjects worked into marble or softer
The advent of synthetic tungsten-carbide
tipped chisels that allow these hard stones to
be worked in much the same manner as
marble often now tends to limit the use of
the Bush Hammer as simply a means of
applying surface texture.
Two examples of the Crandall, a tool in the
Bush Hammer family which has removable
teeth that are held in place by a simple
wedge.
The Crandall was most often used to
surface sandstones that tended to simply flake away if struck with the common type of Bush
Hammer.

31. An example of one type of Bush
Hammer thathas interchangeable faces,
thus allowing one tool to span a wide
range from coarse to fine textures.
Bush Chisels, Frosting Tools, or Matting
Tools are used when a greater degree of control
is needed than the Bush Hammer allows, such
as when working near edges or intersecting
surfaces
Though deceptively similar to the Bush Hammer in
appearance, both the Toothed Stone
Axe and theToothed
StoneHammer are lessused for
workingthe face of thestone and
moreused for chippingaway at the
edges.

32. These examples of Bush
Chisel are all made for use in a pneumatic Carving Hammer. Though long versions are made for
use in an air hammer, the short versions are much easier to use when a high degree of control is
not necessary. This is because the chisel is not held in the hand as the longer versions must be,
but instead are just loosely held in the socket of the hammer slightly above the surface to be
worked. This allows the chisel to 'dance' randomly as the hammer is moved across the surface.
One manufacturer makes several other types of surfacing
tools in a short version so they may be used in the same
manner; the Three Blade Bushing Chisel, the Criss-
Cross Chisel, and the Cup Chisel.

33. SAFETY REGULATIONS REGARDING THE USE
OF DIAMOND TOOLS
GENERAL SAFETY RULES
Incorrectly used diamond tools can be dangerous.
- Follow the instructions of the supplier of the diamond tool and the manufacturer
of the machine.
- Make sure the diamond tool is suited to the use to which it is to be put. Examine
all tools before fitting to ensure that they are free from damage or faults.
- Follow the recommended procedures for the handling and storage of diamond
tools.
- Know the risks of using diamond tools and take the relevant precautions :
- Bodily contact with the diamond tool when operating.
- Injuries caused by the breaking of a diamond tool during use.
- Milling debris, sparks, smoke and dust generated by abrasion.
- Noise.
- Vibration.
- Never use a machine that is not in good condition or has faulty parts.